In previous clip attachment mechanisms, at the outer surface of the rear of the shaft, the radial base section of the forward-extending clip attachment section was formed as a whole, and a clip base section was inserted and fixed into an insertion hole which opened at the end of the forward-extending clip attachment section.
However, in the above example of prior art, because it is a construction in which a clip base section is inserted and fixed into an insertion hole which opens forwardly at the end of the clip attachment section, there are cases in which the fit of the clip base section and the insertion hole is loose due to such factors as dimensional errors, and there are problems such as the lateral shaking and dropping out of the clip.